Following surprising claims this week by South Korean researchers that they cloned an embryo from the cell of a 30-year-old woman, scientists and ethicists said cloning of humans, while controversial, is likely to be achieved sometime soon. “The question isn’t whether they did it or not, but whether there is any scientific reason to believe any top human fertility expert can’t try and even succeed in cloning a human,” said Randall Prather, an animal embryo researcher at the University of Missouri. Dr. Prather and other scientists engaged in animal cloning experiments said that breakthroughs in recent months in cloning mice and cattle, following the cloning of a sheep in early 1997, suggest that duplicating such efforts in humans is, if not possible now, likely to be possible soon. “The science is there, or nearly there,” said Dr. Prather who is attempting to clone pigs.
He noted that, if anything, humans, for technical reasons, “may turn out to actually be easier to clone than some other animal species.” The Korean cloning announcement by fertility doctors Wednesday in Seoul triggered a world-wide response of skepticism and alarm. Most countries, including the U. S. , have called for a moratorium on human cloning research until many ethical and scientific issues are addressed.
Indeed, the Korean researchers said they stopped their experiment after the embryo had developed into only four cells, meaning that it is still unknown whether the cloned embryo could have developed into a viable or full-term and healthy birth. “Even in the animal research we know there is a giant leap from creating a four-cell embryo to creating a live birth,” said Jorge Piedrahita, an embryologist working on cloning pigs and cows at the college of veterinary medic in at Texas A&M University. Dr. Piedrahita said in the successful cloning of mice and cows reported in recent months “many of the cloned embryos didn’t advance to birth, probably because they were defective in some way.” Still, the Korean announcement is being widely seen as evidence that cloning is moving forward much faster than many expected. In February 1997, Ian Wilmut of the Roslin Institute in Scotland stunned the scientific community when he reported the successful cloning of a lamb he named Dolly from the cell of an adult sheep.
Previously, scientists had believed that it wasn’t possible to create a genetic replica of an adult mammal by using genetic material from a cell of an adult. That is because, unlike embryo cells that serve as the basis for all later cells, adult cells have very specific functions that keep their activity restricted. For example, scientists believed muscle cells could only make other muscle cells and nerve cells could only make other nerve cells. But Dr. Wilmut destroyed that belief. This past summer, scientists in Hawaii using a somewhat different technique than was used in Scotland produced numerous clones from the cells of adult mice, and two weeks ago Japanese reserachers produced four calves from a single cow.
In a news conference in Seoul, Lee Bo Yeon, a fertility specialist at Kyung hee University Hospital, said he and his colleague, Kim Sung Bo, used a technique similar to the one used by the Hawaiian scientists. In the experiment, he said he took the genetic material from the nucleus of a cell taken from tissue near the ovum of an infertile woman and substituted it for the genetic material in an egg removed from the same woman. As in the Hawaiian research, the scientists prompted the egg to use the adult genetic material to divide into a four-cell embryo. Dr. Lee said the embryo was then destroyed because of ethical concerns. South Korea restricts human cloning research but doesn’t yet forbid it.
In the U. S. , an ethics commission in 1997 recommended a five-year moratorium on human cloning research and President Clinton has banned the use of federal funds to conduct human cloning experiments. The Korean announcement led biology experts in the U.
S. to question the veracity and ethics of the Korean team. “My first response is that science by press conference in an area as controversial as this is somewhere between despicable and devious,” said Arthur Caplan, who runs the Center for Bioethics at the University of Pennsylvania. Dr. Caplan said there is no way to verify the Koreans’ claim and it raises all sorts of worries that others will be conducting similar experiments in the absence of proof that it is safe or even desirable. “Human cloning claims in the past have been fraught with fraud and misinformation,” Dr.
Caplan said. “This isn’t how scientists with integrity behave.” But several well-respected ethicists grappling with concerns since the cloning of Dolly say that human cloning per se is not necessarily unethical or immoral. “If in fact people want to produce a child that is their biological duplicate there is no reason not to let it occur,” said Lee Silver, a geneticist at Princeton University. Dr. Silver said it may someday be widely acceptable for infertile couples or single infertile women to use cloning as a way to conceive a child biologically related to them.
Norman Fost, a bioethicist at University of Wisconsin, said it may even be acceptable to conceive and raise a child who is a genetic copy in order to use the child as a bone marrow donor. “Right now a lot of the concern about human cloning is based on the fact that people say it makes them feel queasy,” Dr. Fost said. “These so-called queasinartists don’t provide any proof that cloning will create children who are in some way defective or dangerous to society.” Ruth Macklin, an ethicist at Albert Einstein College of Medicine in New York, said the principal concern right now is whether human cloning can be done safely. “There is no evidence, and the Koreans don’t seem to provide any yet either, that you can conceive a child this way without a high risk that the child will be born physically damaged,” she said. She and others said that, in fact, the current moratorium on research may inhibit efforts to assure that human cloning is done safely.
Most ethicists said, however, they expect that much more work must be done in animals, especially primates, before any human cloning should proceed.